From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752244AbaFFRSG (ORCPT ); Fri, 6 Jun 2014 13:18:06 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:58983 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751851AbaFFRSE (ORCPT ); Fri, 6 Jun 2014 13:18:04 -0400 Date: Fri, 6 Jun 2014 19:18:01 +0200 From: Peter Zijlstra To: Rik van Riel Cc: linux-kernel@vger.kernel.org, mgorman@suse.de, mingo@kernel.org Subject: Re: [PATCH] sched,numa: always try to migrate to preferred node at task_numa_placement time Message-ID: <20140606171801.GE11371@laptop.programming.kicks-ass.net> References: <20140604163315.1dbc7b56@cuia.bos.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140604163315.1dbc7b56@cuia.bos.redhat.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 04, 2014 at 04:33:15PM -0400, Rik van Riel wrote: > It is possible that at task_numa_placement time, the task's > numa_preferred_nid does not change, but the task is not > actually running on the preferred node at the time. > > In that case, we still want to attempt migration to the > preferred node. So we have that numa_migrate_retry which was supposed to keep kicking the task until it got where it needed to go. But now you continuously kick from task_numa_placement(). Clearly the retry thing didn't work, what happened? We got to the preferred nid, disabled the retry and got moved away again? Do we want to remove the retry logic in favour of this more aggressive form? > @@ -1575,11 +1575,13 @@ static void task_numa_placement(struct task_struct *p) > + if (max_faults) { > + /* Set the new preferred node */ > + if (max_nid != p->numa_preferred_nid) > + sched_setnuma(p, max_nid); > + > + if (task_node(p) != p->numa_preferred_nid) > + numa_migrate_preferred(p); > } >